Selfpriming centrifugal pump

Abstract

The invention is directed to a selfpriming centrifugal pump having a symmetrical annular guide channel with a centrally mounted cover disc. A pair of guide ribs improve the loading of the impeller and increase the capacity for drawing air by suction. The guide rib pair is mounted in the annular guide channel. Each guide rib includes an injection rib and a separation rib. The ribs preferably have a width corresponding to the width of the annular guide channel and are arranged on a secant drawn through the circular peripheral band defined by the outer tips of the vanes of the impeller as the latter rotates.

What is claimed is: 
     
       1. A selfpriming centrifugal pump for pumping an operating liquid, the centrifugal pump comprising: a pump housing for receiving an operating liquid therein;   a suction branch which is vented when the pumping action is initiated;   a discharge branch;   an impeller rotatably mounted in said housing for rotation in a predetermined direction and so as to be disposed in the operating liquid contained therein for pumping the latter from said suction branch to said discharge branch after the suction branch is vented;   drive means for rotatably driving said impeller;   two mutually adjacent walls arranged on respective sides of said impeller to define a rotationally-symmetrical annular guide channel communicating with said suction branch;   said impeller having a plurality of vanes with respective outer tips tracing an imaginary circular peripheral band as the impeller rotates in said housing, each two mutually adjacent ones of said vanes conjointly defining an impeller cell;   guide means including two ribs having respective end edges, said ribs being mounted in said guide channel so as to place said end edges thereof on a secant drawn through said circular peripheral band near the intersections of said secant with said circular peripheral band;   said ribs being further mounted in said guide channel so as to permit said outer tips and said edges to conjointly define a predetermined clearance therebetween as said vanes rotate past said ribs and so as to extend away from said predetermined clearance in respective directions which are substantially opposite to each other;   a first one of said ribs being an injection rib positioned with respect to the direction of rotation of the impeller so as to direct a portion of said operating liquid in said guide channel back into the cells of the impeller to there establish a liquid/air mixture to draw air out of said suction branch to vent the latter;   the second one of said ribs a separation rib for separating a part of the liquid/air mixture flung into said guide channel into a liquid component and an air component so as to allow the air component to escape upwardly in said housing and to permit the separated liquid component to be directed back into the impeller cells by said injection rib as said liquid component is rotated with said impeller; and,   said injection rib and said separation rib having respective lengths, one of said lengths being greater than the other one of said lengths.   
     
     
       2. The selfpriming centrifugal pump of claim 1, said ribs being linear and mounted in said guide channel so as to lie on said secant. 
     
     
       3. The selfpriming centrifugal pump of claim 1, said ribs being linear and mounted in said guide channel so as to be inclined with respect to said secant. 
     
     
       4. The selfpriming centrifugal pump of claim 1, said ribs being arcuate along their respective lengths. 
     
     
       5. The selfpriming centrifugal pump of claim 1, said two ribs being a first pair of ribs and said guide means comprising a plurality of said pairs of ribs arranged on respective secants drawn through said circular peripheral band. 
     
     
       6. The selfpriming centrifugal pump of claim 1, said ribs being fixedly attached to one of said walls. 
     
     
       7. The selfpriming centrifugal pump of claim 1, said ribs and said end edges thereof having a width corresponding to the width of said annular guide channel.